CD22 [BLCAM/1796] is a type 1 integral membrane glycoprotein with molecular weight of 130 to 140 kDa. It is expressed in both the cytoplasm and cell membrane of B-lymphocytes. CD22 antigen appears early in B-cell lymphocyte differentiation at approximately the same stage as the CD19 antigen (1). CD22 may be a useful marker for phenotyping mature leukemias, as CD22 membrane expression has been shown to be limited to the late differentiation stages between mature B cells (CD22+) and plasma cells (CD22-) (1,2). CD22 is also strongly expressed in hairy cell leukemia (3).
1. Perfetti V, et al. Membrane CD22 defines circulating myeloma-related cells as mature or later B cells. Lab Invest. 1997 Oct;77(4):333-44.
2. Batata A, Shen B. Immunophenotyping of subtypes of B-chronic (mature) lymphoid leukemia. A study of 242 cases. Cancer. 1992 Nov 15;70(10):2436-43.
3. Voigt JJ, et al. Immunochemical diagnosis of hepatic localizations in malignant lymphoid hematologic disease. Study of 80 cases. Gastroenterol Clin Biol. 1989 Apr;13(4):343-52.
4. Center for Disease Control Manual. Guide: Safety Management, NO. CDC-22, Atlanta, GA. April 30, 1976 “Decontamination of Laboratory Sink Drains to Remove Azide Salts.”
5. Clinical and Laboratory Standards Institute (CLSI). Protection of Laboratory Workers from Occupationally Acquired Infections; Approved Guideline-Fourth Edition CLSI document M29-A4 Wayne, PA 2014.